If you have an SSH client, such as Putty - (or if you've hooked up Powershell with SSH), you can SSH localhost:2222 (user: vagrant, pw: vagrant). By far, the easiest way to accomplish an SSH session with your Vagrant instance is to run

$ vagrant ssh my-vm

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.
Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
vagrant@my-vm:~$

From that point, you should be able to sudo su - and maintain a root session.

$ sudo su -

root@my-vm:~#

6) Install Docker CE from command line. I whipped up some instructions here on step #1.

That's it! You can now use the /media/vagrant directory, which essentially mounts your Windows directory via rsync, to utilize Docker development through the Vagrant instance.